KM5TZ 4 x 5 PA construction started (updated 4/2/05)

Post your photos here and write-ups you may have

KM5TZ 4 x 5 PA construction started (updated 4/2/05)

Postby KM5TZ/6 » Sun Feb 27, 2005 9:33 pm

I still have to bolt a few things down and finish it up but I do have it working now on all 3 bands! 160/80/40m.

Here's a pic of the PA section:

Image

Efficiency is just under 90% on 40m and about 92% on 80m and 160m.

David.
KM5TZ
Last edited by KM5TZ/6 on Sat Apr 02, 2005 8:09 pm, edited 4 times in total.
KM5TZ/6
Member
 
Posts: 26
Joined: Mon Dec 13, 2004 1:47 pm

Postby steve_qix » Mon Feb 28, 2005 8:27 am

Very strapping!

I had some problems getting the picture to display - had to copy the URL to the image, and display it directly.

What are you using for RF bypass caps? They LOOK like electrolytics, but I can't tell exactly from the picture. The RF bypass point is a HIGH current point RF-wise, and the bypass capacitor(s) must have both very short leads, and have low internal inductance and resistance.

Sure looks like a nice amp! I'm assuming the extra doorknob caps are for other bands?

Regards,

Steve
Visit the class E web site at:

http://www.classeradio.com
User avatar
steve_qix
Class E Guru
 
Posts: 434
Joined: Fri Jan 31, 2003 11:03 am
Location: Townsend MA

Postby KM5TZ/6 » Mon Feb 28, 2005 1:26 pm

Steve,

Sorry about the pic, looks like my freebie web host does not allow direct link to images. Here's a link, you'll have to scroll to the bottom of the page.

http://www.km5tz.netfirms.com/classe.htm


The bypass capacitors are MKP1845 polypropylene film capacitors. These particular ones are made by ERO in Germany. On each rail (4 of) I have 3 x 0.1uf and a couple of .01 ceramic caps in parallel. They all have short leads. The ground straps on the FET's are extended down the center of each half and pick up the ground on some of these caps. My PDM filter has 3uF on its output and since I 'm adding about 1.2uF of additional capacitance to ground at the PA decoupling point I'll remove 1uF from the PDM filter output.

Yes the extra doorknobs are for other bands. This will be used for 40/80/160.

Thanks for the feedback!

David.
KM5TZ/6
Member
 
Posts: 26
Joined: Mon Dec 13, 2004 1:47 pm

Postby steve_qix » Mon Feb 28, 2005 8:22 pm

It sure looks great!

Do you have pictures of the modulator :-)

Thanks for the update, and please keep us informed.

Regards,

Steve
Visit the class E web site at:

http://www.classeradio.com
User avatar
steve_qix
Class E Guru
 
Posts: 434
Joined: Fri Jan 31, 2003 11:03 am
Location: Townsend MA

Postby KM5TZ/6 » Sun Mar 13, 2005 12:53 am

Pictures updated - scroll to bottom of page.

http://www.km5tz.netfirms.com/classe.htm

David.
KM5TZ
KM5TZ/6
Member
 
Posts: 26
Joined: Mon Dec 13, 2004 1:47 pm

Postby blaine » Sun Mar 13, 2005 10:18 am

very nice! :D
good work.
Blaine N1GTU
"The box said that I needed to have Windows 98 or better...
so I installed Linux." --- LinuxNewbie.org
User avatar
blaine
Site Admin
 
Posts: 98
Joined: Fri Jan 31, 2003 1:13 am
Location: CT

Updated.

Postby KM5TZ/6 » Sat Apr 02, 2005 8:11 pm

Updated.
KM5TZ/6
Member
 
Posts: 26
Joined: Mon Dec 13, 2004 1:47 pm

Postby frank carcia » Sun Apr 03, 2005 10:14 am

VERY NICE JOB,
I think this is the first 3 band warp 1 rig.
frank carcia
Senior Contributer
 
Posts: 765
Joined: Fri Jan 31, 2003 10:48 am
Location: Enfield Ct. / Niantic Ct.


Return to Your Photos and Articles

Who is online

Users browsing this forum: No registered users and 1 guest

cron